Sigma Engine Breather Setup, Engine Breathing Oil

[pilotprice]

Hi Guys

Just a quick one, my 150 engine seems to be breathing a lot of oil into the catch can and I want to check the setup as I'm confused.

My engine has two breathers, one (which I assume is the PCV) is under the inlet manifold and one on the cylinder head valve cover.
I have a catch can with one inlet.
I have fitted a pipe from each breather into a Y joint then run that pipe into the catch can.

Im wondering if that now my PCV doesn't have a vacuum from the inlet or that its sharing the valve cover exit is causing my engine to vent oil into the can, excessively?

Can someone please enlighten me? I don't understand how the PCV can operate without a vacuum, even if your catch can has two entries and their own pipe runs.

Or does this engine not run PCV?

[nigelpugh7]

My new build Superlight Twenty ( Sigma 135 ) came with no oil catch tank as standard.

All was good until I did my first sprint day at Curborough, where after a high speed left, into a hard left corner it would blow large plumes of smoke out of the exhaust.

I spoke with Simon Lambert of CC, who said all sigmas would do that, unless fitted with an oil catch tank, as fitted to the academy race cars, so I ordered the kit straight away.

It I loves blanking the breather on the throttle body, ( single on mine but yours will have TB, so not the same ) then the one pipe from the side of the engine under the intake plenum and the other from the cam cover, both into one single tank with a breather in it.

Smoking problem totally gone now, but it does kick out oil in to the tank.

At our recent evening at Donington, after two hours of hard track use the tank was almost half full, which I reckon is shuts over 1 litre of oil.

I took spare oil with me, and it needed 1 litre approx to get it back to the top level on the dipstick.

So not sure if this is all normal, but seems to be OK to me.

[nigelpugh7]

Forgot to add that yes our Sigma engines ( also known in ford terms as Zetec SE ) do use Positive Crankcase Ventilaion ( PCV) .

Just to answer your question, not sure if it can be changed or improved upon though.

[pilotprice]

You are seeing similar oil consumption to me then I guess, this cannot be considered normal.

Having done some more reading, it appears that restrictions or lack of 'flow' of vented crank gasses can cause excessive blow by and cause the oil to be forced out via the breather.

I'm going to try the following -

Remove the Y union linking both hoses and ur their own respective feeds into the tank and increase the ventilation of the tank it's self by drilling 5:6 more 4mm in the caps on each feed

Is your car running a T or Y connection for both feeds to get it into one entry for the catch can?

[nigelpugh7]

pilotprice said:

You are seeing similar oil consumption to me then I guess, this cannot be considered normal.

Having done some more reading, it appears that restrictions or lack of 'flow' of vented crank gasses can cause excessive blow by and cause the oil to be forced out via the breather.

I'm going to try the following -

Remove the Y union linking both hoses and ur their own respective feeds into the tank and increase the ventilation of the tank it's self by drilling 5:6 more 4mm in the caps on each feed

Is your car running a T or Y connection for both feeds to get it into one entry for the catch can?

Nope the acedemy oil catch tank kit uses two separate pipes into the tank, no t piece or y pipe is used.

[Eccles52]

Well I've just crawled out from the engine bay and I have the "T" piece in the pipe that goes from the rocker cover to the block, and then the branch off from the "T" goes to the catch tank whose lid has a few holes (8mm) drilled in it for venting.

I've never had any oil build up in the catch tank (16K miles) but maybe that's because I don't drive it hard enough!!

[pilotprice]

Ok cool

That's basically the setup I have but I don't have as many breather holes.
I'll have to add some

[pilotprice]

Ok cool

That's basically the setup I have but I don't have as many breather holes.
I'll have to add some

[Camoradi]

Hi Nigel, is this the kit in question, please, and does it come with some sort of plumbing instructions?

http://caterhamparts.co.uk/product.php?id_product=...

thanks

Kevin

[nigelpugh7]

Camoradi said:

Hi Nigel, is this the kit in question, please, and does it come with some sort of plumbing instructions?

http://caterhamparts.co.uk/product.php?id_product=...

thanks

Kevin

Hi Kevin,

No it's not that one, but it is that tank.

My kit is the as below, ordered it direct from Darren at cc.

The engine breather kit is part number 36EB01AK and price is £33 plus vat (and postage).

If you can please let me have a delivery address and contact number I will give you a call to obtain payment details.

Regards

Darren Phillips
Aftersales Commercial Manager
<image001.jpg>

Kennet Road, Dartford, DA1 4QN, UK
E: [e-mail] | T: [phone] | M: [phone]
www.caterhamcars.com

However it comes with a very nice large 2 litre oil tank, but this is intended for acedemy cars that don't have a heater , and to be mounted on the bulkhead, but as I had a heater it would not go there or anyway else at the front.

So cc sent me the smaller tank,,as you have showed in the picture. So I could fit it where you see it mounted.

Personally on reflection I think it's quite expensive at over £50 inc vat and delivery, any tank would do, with the pipes to the block and cam cover.

Something like this would be more than adequate .

http://www.ebay.co.uk/itm/Oil-Catch-Can-10mm-Light...

[Camoradi]

Thanks Nigel,

Like you I think a 1 litre tank is enough, so I'll go for the smaller one and sort out my own hoses etc. I found a plumbing diagram here

http://www.pistonheads.com/gassing/topic.asp?t=136..., and it's pretty simple (i think)

Cheers

Kevin